/*
 * Copyright � 2002-2011 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

using System.Collections;
using System.Runtime.Serialization;

namespace Spring.Expressions;

/// <summary>
/// Represents parsed variable node.
/// </summary>
/// <author>Aleksandar Seovic</author>
[Serializable]
public class LocalVariableNode : BaseNode
{
    //internal const string LOCAL_VARIABLES = "__locals";

    /// <summary>
    /// Create a new instance
    /// </summary>
    public LocalVariableNode()
    {
    }

    /// <summary>
    /// Create a new instance from SerializationInfo
    /// </summary>
    protected LocalVariableNode(SerializationInfo info, StreamingContext context)
        : base(info, context)
    {
    }

    /// <summary>
    /// Returns value of the local variable represented by this node.
    /// </summary>
    /// <param name="context">Context to evaluate expressions against.</param>
    /// <param name="evalContext">Current expression evaluation context.</param>
    /// <returns>Node's value.</returns>
    protected override object Get(object context, EvaluationContext evalContext)
    {
        string varName = this.getText();
        IDictionary locals = evalContext.LocalVariables;
        if (locals != null)
        {
            return locals[varName];
        }

        return null;
    }

    /// <summary>
    /// Sets value of the local variable represented by this node.
    /// </summary>
    /// <param name="context">Context to evaluate expressions against.</param>
    /// <param name="evalContext">Current expression evaluation context.</param>
    /// <param name="newValue">New value for this node.</param>
    protected override void Set(object context, EvaluationContext evalContext, object newValue)
    {
        string varName = this.getText();
        IDictionary locals = evalContext.LocalVariables;
        if (locals == null)
        {
            locals = new Hashtable();
            evalContext.LocalVariables = locals;
        }

        locals[varName] = newValue;
    }
}
